I think you're overstating this based on the internet. Sure, there are aggressively intolerant folks and maybe too many for this to work.
But the vast majority of folks aren’t going to get into a flame war over diner while staring into someone’s face. They might say crude things but they’ll probably also learn something.
I think the only thing that makes this idea really questionable is the proliferation of firearms in American culture
It's a little bit different when it's outside the family, though. Inside the family, a homophobic parent might feel emasculated, or like a failure, if their kid turns out to be gay. But when meeting an adult gay couple at a social function, or working with a gay colleague, the same person will probably at least remain cordial, if not explicitly supportive.
But the vast majority of folks aren’t going to get into a flame war over diner while staring into someone’s face. They might say crude things but they’ll probably also learn something.
I think the only thing that makes this idea really questionable is the proliferation of firearms in American culture